Simple microwave‐assisted ligand‐free suzuki cross‐coupling: Functionalization of halo‐pyrimidine moieties

An advantageous ligand‐free protocol for Suzuki couplings is described. The synthetic procedure entails microwave irradiation for the reduction of the reaction times and the use of silica cartridges for the purification. Dihalo‐pyrimidine structures, interesting scaffolds in medicinal chemistry, were chosen as test compounds.     

Synthesis and anti‐HIV‐1 evaluation of 1,5‐disubstituted pyrimidine‐2,4‐diones

1,5‐Disubstituted pyrimidine‐2,4‐diones were synthesized by fusion of 5‐bromouracil with an aniline derivative followed by coupling with benzyl halide whereas the opposite synthesis sequence failed. Also 4,6‐dichloro‐N,N,5‐trimethylpyrimidin‐2‐amine was treated with phenols. The products were tested for their activity against HIV‐1.     

Synthesis of an 4‐oxo‐1,4‐dihydropyridinomethylidene substituted 2‐indolinone

The (Z)‐3‐substituted 2‐indolinone 6 was prepared using the aldehydes 4 and 8 unknown up to now and 2‐indolinone.     

Synthesis of new di‐ and tetraazadibenzosulfoxide macrocycolic compounds

Novel macrocyclic di and tetraamide compounds have been synthesized by the reaction of 2‐2′‐sulfoxide‐bis‐(4‐methyl phenoxy) aceticester or aceticacid chloride) (obtained from corresponding bisphenol) with appropriate diamines. Also the results of the presence of base as template are discussed and compared.     

Microwave‐assisted efficient synthesis of benzo[4,5]imidazo[1,2‐a]‐pyrimidine derivatives in water under catalyst‐free conditions

Benzo[4,5]imidazo[1,2‐a]pyrimidine derivatives were synthesized via the three‐component reaction of aldehyde, β‐dicarbonyl compound and 2‐aminobenzimidazole in water under microwave irradiation and without catalyst conditions. The new protocol has the advantages of higher yield, lower cost, reduced environment impact, wider scope and convenient procedure.     

A facile three‐components,one‐pot synthesis of pyrimido[4,5‐d]pyrimidine‐2,5‐dione derivatives under microwave‐assisted conditions

Pyrimido[4,5‐d]pyrimidine‐2,5‐dione derivatives have been synthesized in high yields in a novel, onepot, and efficient process by condensation of 6‐amino‐3‐methyl‐2‐(methylthio)pyrimidin‐4(3H)‐one, aldehydes and urea under microwave‐assisted conditions.     

Solvent‐free synthesis of 5‐methyl‐7‐aryl‐4,7‐dihydrotetrazolo[1,5‐a]pyrimidine‐6‐carboxylic esters catalyzed by sulfamic acid

The solvent‐free synthesis of 5‐methyl‐7‐aryl‐4,7‐dihydrotetrazolo[1,5‐a]pyrimidine‐6‐carboxylic esters was performed and effectively catalyzed by sulfamic acid. Compared with conventional methods, this protocol features mild reaction conditions and high yields. Furthermore, it is solvent‐free and thus eco‐friendly.     

Convenient synthesis of c2‐symmetric diazepinium salts derived from 1,1′‐binaphthyl‐2,2′‐diamine

New C₂‐symmetric atropisomeric diazepinium salts were prepared utilizing Vilsmeier‐Haack activation of corresponding formamide precursors by phosgene solution in toluene. The structures of these substances were verified by X‐ray diffraction.     

Synthesis of 5‐[(4‐phenylpiperazin‐1‐yl)methyl]pyrrolo‐[2,3‐d]pyrimidine derivatives as potential dopamine D4 receptor ligands

A series of pyrrolo[2,3‐d]pyrimidine Mannich bases of type 9, 12, 15 and 16 have been prepared as potential dopamine D4 receptor ligands. The syntheses start from 4‐aminopyrimidin‐6‐one 3 with pyrrole annulations and Mannich reactions with formaldehyde and phenylpiperazines 8 as new amine components.     

Synthesis and antimicrobial activity of some new N‐(substituted phenyl)‐N′‐[2,3‐dihydro‐2‐oxido‐3‐(4′‐fluorophenyl)‐1H‐(1,3,2)benzoxazaphosphorin 2‐yl]ureas

Substituted benzoxazaphosphorin 2‐yl ureas were synthesized by reacting 2‐(4‐fluoro‐phenylamino)‐methylphenol (4) with different carbamidophosphoric acid dichlorides (3) in the presence of triethylamine in dry toluene at 45‐50 °C and characterized by spectral data. These compounds were found to possess good antimicrobial activity.     

Convenient way to 5‐substituted 4‐amino‐2,3‐dihydro‐4H‐1,2,4‐triazole‐3‐thiones

Various 4‐amino‐2,3‐dihydro‐4H‐triazoles with aromatic, aliphatic and heterocyclic substituents at the C(5) position were synthesized from corresponding esters and thiocarbohydrazide. This method allows the synthesis these heterocycles in a short time and at reduced expenses.     

A convenient synthesis of 5‐alkylthio‐3,4‐diarylisoxazoles by palladium‐catalyzed coupling reactions

Palladium‐catalyzed coupling reaction was found effective for rapid access to pharmacologically interesting 3,4‐diarylisoxazoles derivatives as selective COX‐2 inhibitors. Thus, the coupling reaction between 5‐alkylthio‐3‐aryl‐4‐iodoisoxazoles and arylboronic acids afforded the target 5‐alkylthio‐3,4‐diarylisoxazoles in good yields.     

Synthesis and herbicidal activity of 2‐(3‐(trifluoromethyl)‐5‐(alkoxy)‐1H‐pyrazol‐1‐yl)‐4‐aryloxypyrimidine derivatives

A series of 2‐(3‐(trifluoromethyl)‐5‐(alkoxy)‐1H‐pyrazol‐1‐yl)‐4‐aryloxypyrimidine derivatives were designed and synthesized. The structures of all the title compounds were confirmed by ¹H NMR and elementary analysis. These compounds were screened for herbicidal activity against rape and barnyard grass. Compound B13 exhibited moderate herbicidal activity.     

Synthesis of 2,2′‐bipyridyl‐type compounds via the suzuki‐miyaura cross‐coupling reaction

2,2′‐Bipyridyl‐type compounds may be prepared by Suzuki‐Miyaura coupling of a 2‐pyridylboronic ester with 2‐haloazines and ‐azoles. Ten examples are presented with yields of 47 to 84%. Both arylbromides and arylchlorides undergo the coupling, but the reaction is sensitive to ring substitution adjacent to the halogen.     

A facile one‐pot synthesis of 2‐amino‐4‐arylbenzo[h]quinoline‐3‐carbonitrile derivatives without catalyst

A series of 2‐amino‐4‐arylbenzo[h]quinoline‐3‐carbonitrile derivatives were synthesized by one‐pot condensation of aromatic aldehyde, a‐naphthylamine and malononitrile in ethanol without catalyst. This multicomponent reaction has the notable advantages of short route, high yield and convenient operation.